This invention relates to shaped articles formed from blends of rubber and plastic, and to a method for making them.
It is known to make shaped articles from thermoplastic materials by molding or extruding them from the thermoplastic materials in a fluid state, then cooling them to the solid state. Articles so made have the disadvantage that their service temperatures are limited by the melting (or softening) point of the materials. If exposed to service temperatures in excess of the melting (or softening) point, the articles lose their dimensional integrity.
Thermoplastic elastomers have been developed which have the rubbery characteristics of elastomers, but can be shaped as thermoplastics. Here again, the service temperatures of articles formed from these materials are limited by the melting (or softening) points of the elastomers.
If rubbery qualities are desired in an article, conventional thermoset rubber can be used, however, both heat and pressure are required to produce thermoset articles, and even the fastest vulcanizing rubber compounds require much more molding time than typical thermoplastics. Scrap from thermoset rubber production cannot be reworked.